1. Technical Field
The present technology relates to a pneumatic run flat tire, and particularly Relates to a pneumatic run flat tire in which tire weight can be reduced while maintaining run-flat durability, and which is configured so that riding comfort when regular traveling is enhanced.
2. Related Art
Conventionally, in run flat tires provided with a reinforcing rubber layer having a falcated cross-section on an inner surface side of a side wall portion, methods such as increasing a thickness of the reinforcing rubber layer and using a rubber with a higher hardness for the reinforcing rubber layer have been used in order to ensure durability when run-flat traveling. However, there are problems with tires having run-flat durability enhanced in this way such as increased rolling resistance caused by increased weight, and worsening of riding comfort when regular traveling caused by increased side stiffness.
Conventionally, using a particular rubber as the material of the reinforcing rubber layer and compounding short fiber in the material of the reinforcing rubber layer have been proposed as measures to enhance run-flat durability while enhancing riding comfort when regular traveling (see Japanese Unexamined Patent Application Publication No. 2005-343372A). However, with both of these proposals, the enhancement of riding comfort when regular traveling and the reduction of tire weight is insufficient, and there is still room for improvement.